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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 422 | giacomo | 1 | /* zutil.h -- internal interface and configuration of the compression library |
| 2 | * Copyright (C) 1995-1998 Jean-loup Gailly. |
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| 3 | * For conditions of distribution and use, see copyright notice in zlib.h |
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| 4 | */ |
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| 5 | |||
| 6 | /* WARNING: this file should *not* be used by applications. It is |
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| 7 | part of the implementation of the compression library and is |
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| 8 | subject to change. Applications should only use zlib.h. |
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| 9 | */ |
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| 10 | |||
| 11 | /* @(#) $Id: zutil.h,v 1.1 2004-01-28 15:27:06 giacomo Exp $ */ |
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| 12 | |||
| 13 | #ifndef _Z_UTIL_H |
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| 14 | #define _Z_UTIL_H |
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| 15 | |||
| 16 | #include <linux/zlib.h> |
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| 17 | #include <linux/string.h> |
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| 18 | #include <linux/errno.h> |
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| 19 | #include <linux/kernel.h> |
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| 20 | |||
| 21 | typedef unsigned char uch; |
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| 22 | typedef unsigned short ush; |
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| 23 | typedef unsigned long ulg; |
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| 24 | |||
| 25 | /* common constants */ |
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| 26 | |||
| 27 | #ifndef DEF_WBITS |
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| 28 | # define DEF_WBITS MAX_WBITS |
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| 29 | #endif |
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| 30 | /* default windowBits for decompression. MAX_WBITS is for compression only */ |
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| 31 | |||
| 32 | #if MAX_MEM_LEVEL >= 8 |
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| 33 | # define DEF_MEM_LEVEL 8 |
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| 34 | #else |
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| 35 | # define DEF_MEM_LEVEL MAX_MEM_LEVEL |
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| 36 | #endif |
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| 37 | /* default memLevel */ |
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| 38 | |||
| 39 | #define STORED_BLOCK 0 |
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| 40 | #define STATIC_TREES 1 |
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| 41 | #define DYN_TREES 2 |
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| 42 | /* The three kinds of block type */ |
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| 43 | |||
| 44 | #define MIN_MATCH 3 |
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| 45 | #define MAX_MATCH 258 |
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| 46 | /* The minimum and maximum match lengths */ |
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| 47 | |||
| 48 | #define PRESET_DICT 0x20 /* preset dictionary flag in zlib header */ |
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| 49 | |||
| 50 | /* target dependencies */ |
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| 51 | |||
| 52 | /* Common defaults */ |
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| 53 | |||
| 54 | #ifndef OS_CODE |
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| 55 | # define OS_CODE 0x03 /* assume Unix */ |
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| 56 | #endif |
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| 57 | |||
| 58 | /* functions */ |
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| 59 | |||
| 60 | typedef uLong (*check_func) (uLong check, const Byte *buf, |
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| 61 | uInt len); |
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| 62 | |||
| 63 | |||
| 64 | /* checksum functions */ |
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| 65 | |||
| 66 | #define BASE 65521L /* largest prime smaller than 65536 */ |
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| 67 | #define NMAX 5552 |
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| 68 | /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */ |
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| 69 | |||
| 70 | #define DO1(buf,i) {s1 += buf[i]; s2 += s1;} |
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| 71 | #define DO2(buf,i) DO1(buf,i); DO1(buf,i+1); |
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| 72 | #define DO4(buf,i) DO2(buf,i); DO2(buf,i+2); |
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| 73 | #define DO8(buf,i) DO4(buf,i); DO4(buf,i+4); |
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| 74 | #define DO16(buf) DO8(buf,0); DO8(buf,8); |
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| 75 | |||
| 76 | /* ========================================================================= */ |
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| 77 | /* |
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| 78 | Update a running Adler-32 checksum with the bytes buf[0..len-1] and |
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| 79 | return the updated checksum. If buf is NULL, this function returns |
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| 80 | the required initial value for the checksum. |
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| 81 | An Adler-32 checksum is almost as reliable as a CRC32 but can be computed |
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| 82 | much faster. Usage example: |
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| 83 | |||
| 84 | uLong adler = adler32(0L, NULL, 0); |
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| 85 | |||
| 86 | while (read_buffer(buffer, length) != EOF) { |
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| 87 | adler = adler32(adler, buffer, length); |
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| 88 | } |
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| 89 | if (adler != original_adler) error(); |
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| 90 | */ |
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| 91 | static inline uLong zlib_adler32(uLong adler, |
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| 92 | const Byte *buf, |
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| 93 | uInt len) |
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| 94 | { |
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| 95 | unsigned long s1 = adler & 0xffff; |
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| 96 | unsigned long s2 = (adler >> 16) & 0xffff; |
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| 97 | int k; |
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| 98 | |||
| 99 | if (buf == NULL) return 1L; |
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| 100 | |||
| 101 | while (len > 0) { |
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| 102 | k = len < NMAX ? len : NMAX; |
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| 103 | len -= k; |
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| 104 | while (k >= 16) { |
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| 105 | DO16(buf); |
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| 106 | buf += 16; |
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| 107 | k -= 16; |
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| 108 | } |
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| 109 | if (k != 0) do { |
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| 110 | s1 += *buf++; |
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| 111 | s2 += s1; |
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| 112 | } while (--k); |
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| 113 | s1 %= BASE; |
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| 114 | s2 %= BASE; |
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| 115 | } |
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| 116 | return (s2 << 16) | s1; |
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| 117 | } |
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| 118 | |||
| 119 | #endif /* _Z_UTIL_H */ |